The summary is that many studies seem to show that a plant-based diet helps prevent and fix most of the diseases that cause the most deaths.
I would do that if I ever got really sick.
People that eat a plant-based diet are more likely to pay attention to their diet, so some of the benefit might come just from paying attention.
The comparison with other diets doesn’t differentiate likely unhealthy (such as fried chicken wings and fried eggs) from likely healthy (such as cooked chicken breast and boiled eggs).
Plant-based diet needs to be complemented with B12 and might need something else we don’t yet know about.